This document describes the design of a 100W solid state power amplifier (SSPA) operating at 13.56MHz. It includes a block diagram showing the input and output matching circuits. The input matching circuit aims to match the 50 ohm source impedance to the 4.5 ohm transistor impedance. The output matching circuit aims to match the 7 ohm transistor impedance back to the 50 ohm load. Simulation results show near perfect power transfer in both matching circuits. In conclusion, the designed SSPA meets specifications by properly selecting the MOSFET transistor and implementing input and output impedance matching circuits.